1. Field of the Invention
The present invention relates generally to preventing foreign materials from being introduced into a plant system. Particularly, the present invention relates to a temporary barrier cover for a pipe-like or similar component of the plant system, which is opened during maintenance of the plant system. More particularly, the present invention relates to a temporary barrier cover for pipe-like components that prevents foreign materials from getting into the opened pipe-like component.
2. Description of the Prior Art
All industrial plant systems at one time or another must undergo maintenance type operations. These maintenance operations may typically involve the disconnection or opening of pipe-like components important in operating the plant systems. When pipe-like components are disconnected or opened, there is the potential of introducing foreign material into the plant system. If this were to occur and the foreign material went undetected, this could cause severe or even catastrophic consequences. In fact, the chance of a catastrophic failure of vital plant equipment has a high probability of occurring. For example, if a bolt, nut, or even a tool were accidentally or inadvertently dropped into a disconnected/opened pipe-like component and the pipe-like component was reassembled and the plant system brought back online, the foreign material would likely become lodged into plant equipment such as a pump, or valve, etc. Repair would cause the plant system a significant amount of money, which could total in the millions of dollars. If this occurs at a nuclear power plant, radiological exposure to the personnel is possible. To preclude this from happening, a temporary cover is placed over any opening in the pipe-like component during maintenance.
The main purpose of placing a cover over an opening of a pipe-like component is to prevent foreign material from falling into the pipe-like component through the component's opening. There are several types of covers currently available on the market. Some of them are made out of fabric-like material and placed over the component's opening. Others are made out of plastic, such as plugs or end caps for pipes, and can be placed over or inside the pipe-like component.
The common disadvantage of currently available covers, however, is that they either restrict the airflow or fully prevent it. Under certain conditions rather common during maintenance type operations, restriction or absence of the airflow not only prevents a cover from serving its intended purpose, but also causes the cover to become a foreign material introduced into the component on which it used as a cover. For example, a negative pressure could be created within a covered pipe-like component. When the pressure difference between the inside and the outside of the pipe-like component is high, the cover placed onto the pipe-like component will be sucked into that component. Thus, the cover itself becomes a foreign material that could damage the plant system.
Another problem caused by the airflow restriction of prior art covers is that some plant systems could implode when prior art covers are used. For example, a storage tank requires an air purge. Restricting the airflow when the inside of the storage tank has a negative pressure relative to the outside of the storage tank causes the storage tank's walls to collapse. This occurs because the tank is engineered to hold water, and not to prevent the tank's walls from caving in.
Therefore, what is needed is a material exclusion cover that prevents foreign material from getting into the pipe-like component of a plant system, but allows air to pass through when air pressure inside the component differs from the air pressure outside the component. What is further needed is a material exclusion cover that is easy to use and maintain.